TM 11-6130-413-40
(3) The normal resistance of replacement parts
chart were made with the equipment disconnected
may differ slightly from the values given in the chart.
from the power source and external battery.
a. Note that each semiconductor j unction resistance
conductors aree listed below:
measurement has two values: the lower resistance
value represents the forward bias resistance; while the
Part
Measured between terminals
Dc resistance
higher resistance value represents the reverse bias re-
(ohms l0%)
sistance. Be sure to check the polarity of the multim-
O to 31 (either secondary
Less than l ohm
T1
eter leads before making measurements.
terminal)
b. Transistor junction resistance measurements pro-
0 to ll0(tertiary)
4 ohms
vide a quick check and will usually reveal open or
Less than l ohm
0 to +5%(primary)
shorted transistors. However, when a specific transis-
0 to -5%(primary)
Less than l ohm
0 to 208 (primary)
Less than l ohm
tor is indicated as being associated with a circuit fault,
0 to 230(priInary)
Less than l ohm
it is advisable to check the transistor by substitution;
370 ohms
A1K1, A1K2 Across coil terminals
alternatively, the transistor may be removed from cir-
Across coil terminals
225 ohms
K1
cuit and tested with the aid of Transistor Test Set
180 ohms
Across coil terminals
K2
TS-1836/U. Also note that erroneous readings can
Across filter terminals
FL1, FL2
Less than l ohm
indicate that an associated circuit component is defec-
tive such as a shorted diode, leaky capacitor, or off-
3-8. Semiconductor Resistance Measure-
value resistor. Check components before replacing
ments
transistors.
c. Transistor Junction Resistance Readings.
The resistance measurements given in the following
Remarks
between terminals (ohms)
C(+)
C(-)
E(+)
E(-)
B(+)
B(-)
lOOK
100K
100K
8 to
8 to
100K
See Note
20
20
(minn)
(min)
(min)
(min)
8 to
100K
100K
8 to
100K
100K
(min)
See Note
20
20
(min)
(min)
(min)
100K
100K
8 to
8 to
100K
100K
See Note
20
20
(min)
(min)
(min)
(min)
8 to
8 to
100K
l00K
100K
100K
See Note
20
20
(min)
(min)
(min)
(min)
8 to
100K
l00K
8 to
l00K
100K
See Note
20
20
(min)
(min)
(min)
(min)
8 to
8 to
100K
100K
100K
100K
See Note
20
20
(min)
(min)
(min)
(min
Q1 through Q6 are parallel-connectd Readings given are for out-of-circuit measurements.
Section III. REMOVAL, REPLACEMENT AND ADJUSTMENTS
3-9. General Parts Replacement Tech-
on printed circuit boards. Excessive soldering heat can
niques
damage componenets or printed wiring.
d. When removing and replacing control knobs, pre-
The following general precautions should be observed
set the control to a readily identifiable position and in-
when replacing parts in this equipment.
stall replacement control knobs to line up in exactly
a. For parts removal and replacement, always work
the same position.
on a clean, flat work surface. When reassembling me-
chanical parts, make sure that mating surfaces are
CAUTION
clean and free of nicks, burns, or surface irregularities.
Avoid using a soldering gun when repairing
Blow out interior of cases with clean compressed air
transistor or IC circuits; damaging voltage
source.
can be induced into components.
b. Whenever an electrical part such as a transistor,
e. Use a cross tip screwdriver to loosen or tighten
diode, IC, resistor, capacitor, etc., is to be removed,
Phillips head screws. Use a hand screw starter to re-
note the exact position of the part before removing it.
move loosened Phillips head screws or to hold and
Replace the part in the same position.
start Phillips head screws.
c. Use a low-wattage soldering iron (25 watts maxim-
um) when replacing components or repairing wiring
permits, use a heat sink (such as long-nosed pliers) be-
3-8
